1. Field of the Invention
The present invention relates to a touch screen apparatus, and more particularly, to a touch screen apparatus for detecting a touch position by sensing a change in capacitance caused by a user's input operation (touch).
2. Description of the Related Art
In general, a touch screen panel (TSP) is used as an input unit. A resistance-type touch screen apparatus is widely used as such touch screen panel. That is, resistance in the touched region is changed by the force applied when a user touches the touch screen panel. A touch position in the touch screen apparatus can be detected by sensing a resistance change.
Such a resistance-type touch screen panel includes an upper substrate and a lower substrate spaced apart from each other. Typically, lower touch lines are provided on the lower substrate and conductive protrusions are provided on the upper substrate. When a touch screen panel is touched, the conductive protrusion is brought into contact with a touch line by the force applied, and changes the resistance of the touch line positioned under the touch region. The position touched can be detected by sensing the change in the resistance of the touch line through a sensing circuit.
In the conventional resistance-type touch screen panel described above, the conductive protrusion of the upper substrate is brought into contact with a touch line of the lower substrate by the force applied on the touch screen panel. Therefore, it is difficult to secure a desirable process margin when manufacturing the touch screen panel. In addition, when the gap between the upper and lower substrates of the touch screen panel is reduced due to extended use, the conductive protrusion may connect to the touch line even in the absence of an applied force. For this reason, the resistance-type touch screen panel is not a satisfactory input device. Further, when the touch screen panel is integrated with a display panel, the requirements for providing the touch lines on the lower substrate, and conductive protrusions on the upper substrate, further complicates the process and design conditions for manufacturing the display panel.